Single-Celled Algae - Definition, Glossary, Details - Oilgae
Any of several divisions of simple photosynthetic organisms, esp. certain thallophytes, variously one-celled, colonial, or filamentous, containing chlorophyll and other pigments (esp. red and brown), and having no true root, stem, or leaf: algae are found in water or damp places, and include seaweeds and pond scum - Source
Photosynthetic unicellular algae have a unique visual system. In Chlamydomonas reinhardtii, the pigmented eye comprises the optical system and at least five different rhodopsin photoreceptors. Two of them, the channelrhodopsins, are rhodopsin-ion channel hybrids switched between closed and open states by photoisomerization of the attached retinal chromophore. They promise to become a useful tool for noninvasive control of membrane potential and intracellular ion concentrations. Source
